<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <!-- 

    width:calc(100% - 10px)
   -->
</head>
<body>
  <div id="app">
    <div :style="{width:100+200+'px',height:'300px',backgroundColor:'red'}"></div>
  </div>
  <script src="./vue.js"></script>
  <script>
    const vm = new Vue({
      el:'#app',
      data:{
       
      }
    })
  </script>
</body>
</html>
